1. Field of the Invention
The present invention relates to electrical connectors having a board latch.
2. Description of the Prior Art
An electrical connector of this type is described in U.S. Pat. No. 4,850,892, for example. The electrical connector includes an insulating housing having a slot for receiving an edge of a board. The board receiving slot has a number of contact terminals arranged along the length thereof. The contact terminals are brought into contact with respective conductive contacts of the board inserted in the slot.
Latch arms and abutment walls are provided on opposite sides of the slot. The latch arms extend upwardly from the bottom wall of the housing and have a latch portion on a free end and are resiliently deflectable in the longitudinal direction of the housing.
To connect a board to the electrical connector, the edge portion of the board is inserted into the slot at angles to a vertical plane. The contacting forces between the edge portion and the contact terminals of the slot are designed to be substantially zero to make the so-called "zero insertion force (ZIF)" configuration. Then, the board is turned downwardly so that the upper portion of the board abuts the abutment walls of the housing. At this point, the opposite sides of the board push the latch arms outwardly so that the board passes the latch portions of the latch arms. When the board abuts the abutment walls, the latch arms resiliently return to the original position so that the board snaps into the latch portions. Under this condition, the conductive contacts of the board are brought into contact with the contact terminals while the board is held between the abutment walls and the latching portions.
To remove the latched board from the electrical connector, the latching posts are resiliently deflected outwardly so that the board passes the latching portions. Then, the board is turned downwardly and pulled up from the slot. The pull out forces are also substantially zero.
In the above electrical connector, however, the latch arms are molded integrally with the insulating housing, and the joints of the latch arms are on the upper surfaces of the connector fixing portions so that the effective resilient length is so short that the latch arms can be broken when the board is removed.
In order to solve such a problem it has been proposed to use metal latch arms. However, this solution increases the number of parts and the unit manufacturing cost. In addition, the latch arms can still be broken when the board is pulled out. The metal latches are difficult to bent at acute angles, and the angled portions are dangerous to handle. The metal latches lacking an acute angle bend fail to provide a snap feeling upon insertion of the board or complete board insertion. Moreover, small vibrations can release the latch, causing not only poor contact of the contact terminals but also loss of memory in the computer.